Objectives: To assess the effect on the fibrinogen concentration of sleep disturbance and mental stress, taking into account the effect of 21 other variables related to the risk of cardiovascular disease.
Design: A cross-sectional study on men threatened by redundancy, and controls.
Setting: A health screening programme in Malmö, Sweden.
Subjects: Four hundred and eighty five workers in a shipbuilding yard, scheduled for closure, and 190 age-matched men. The subjects were randomly selected from a larger group of shipyard workers and controls invited to a health screening programme. Mean age was 51.6 years (range 38-62 years).
Main outcome measures: Plasma fibrinogen concentration, serum cortisol concentration, body composition, blood pressure, heart rate, blood lipids, platelet number and size, white blood cell count, haemoglobin concentration, vital capacity, liver enzymes, blood glucose concentration fasting and after an oral glucose tolerance test. Questionnaire designed to evaluate muscle tension, sleep disturbance, anxiety, depression, job stress, alcohol and smoking habits and perceived health.
Results: In stepwise regression analysis fibrinogen concentration was found to be correlated to white blood cell count, muscle tension, heart rate, body mass index, age and serum cholesterol concentration in non-smokers, which together explained 14.9% of the variation in fibrinogen concentration. In smokers, platelet count, heart rate, serum triglyceride concentration, age and fasting glucose explained 22.5% of the variation in fibrinogen concentration. The fibrinogen concentration was inversely correlated to the psychological variables, but unrelated to the serum cortisol concentration or to factors connected with the job situation, and it was decreased in moderate alcohol consumers.
Conclusions: Our interpretation of the findings is that an increase in the plasma fibrinogen concentration reflects the presence of a low-grade inflammatory process, and poor physical fitness.